Develop Reference

iOS and Android Code GIT Clone conundrum

I have been working on a project for both native iOS and Android apps. Now that my parent projects are done, I need to run clones for them. These clones will use more or less the same code but with different languages, resources and possibly XIB files as well. I have been using GIT for code management and I google the best way to handle this and the suggested technique was with Forking which was no good because it started creating issues with different Package IDs in the projects.
Now, you know the problem that I am facing. I am looking for expert opinion to handle this scenario.

Don't know how about Android, but for iOS you can use targets and then set which files should be used by selected target. Each target may have its own Info.plist file, different graphic assets and more.
Start with duplicating an existing target:
You will notice Info-copy.plist file, which is a setting file for the new target.
Then use a proper scheme to run your new target:
If it's not there, go to "Manage schemes" and press "Autocreate schemes now"

Multiple targets using same android project in eclipse ADT

I have a base android project that gets tweaked and would like to generate different APKs. Typically the changes are help links, icons/images, hiding certain functions etc.
In iOS (Xcode) and in Win store app (VS 2012 exp), it is possible to create multiple targets to control the resources bundled with the target as well us programmatically change behavior using the C flags.
Is it possible to do the same for an android project using eclipse ADT? The main issue I see is that, each APK changes the bundle signature (like com.xxx.yyy) and since every file has that package com.xxx.yyy in the files, it is not possible to use that file in a different project (which has a signature like comm.aaa.bbb).

In eclipse .apk builds with Ant and don't support multiple APKs build. Of course you can write your own script, but it will be difficult.
Fortunately, there is another build system, which is called Gradle and it's supported by android developers.
http://tools.android.com/tech-docs/new-build-system/user-guide
You are interested in a section called "Build Variants"
But not everything is so simple, Eclipse with ADT and Gradle are not compatible but Android Studio yes.

The source of this problem is Java itself, where you can't have things similar to #ifdef and most compiler don't allow completely replacing a class or part of it either.
I actually have a base project from which I build 6 APKs already, and more soon.
Each APK uses its own package name, however the whole code is under a single package, but that doesn't create any issue.
There's however many issues:
- All resources, all classes will be in the target APKs, whether used or not.
- Different behavior means different code or different resources, each of which must be handled differently.
For resources, it's "quite easy", just make replacement resources in the final application projects. However unused resources will be left over.
For classes, that's where it becomes very complicated.
To create slightly different behavior you can use reflection and interfaces, each APK implementing it's own version of the interface using a common name eg myActivityPrj which is retrieved using reflection.
Sometimes it's also easier to test the APK package name from within the code, so in the Application object, I set some boolean as to which APK is actually running. Making sure to use those only from the UI to avoid any performance hit.
To create very different behavior, for example an activity is not used in an APK, well, could use above method and a flag saying available or not, but what a waste of space inside the APK!
Another option is to break-down the central project in smaller pieces, if at all possible!
To actually make APK smaller, I found only one way so far: create a Java project which will copy the central project and then remove and/or replace files within this copy, from a remote source tree (a directory named "replacement-files" which contains a res and src folder).
For resources, that java project will actually parse all strings.xml and remove unused strings from a hard-coded list, can't trust lint output as some resources are used in sub-projects and lint doesn't care.
So far, the APK that includes all features is about 10MB, one variation is about 4MB, whereas it should actually be less than 2MB. Another variation is about 8MB, whereas it should really be 2 or 3MB. The above method is overly complicated and being able to removed unused code and resources is getting more and more complicated.
I've looked at various other solutions, but they're all very complicated with a lot of restrictions, constraints.
After 4 years of development on Android, my only conclusion is that Java is the poorest choice possible for a mobile device: slow, inefficient, resource hungry, and very inflexible. Looking at the NDK, it appears very inconvenient and very limited.

Easily make a copy of my android application

I have an android application for one client, and he wants to make a 99% similar app for different country.
Almost everything is the same, only a few bitmaps would need to be replaced, address of API server will change, language file will change, but the code should stay the same, BUT I will need a different package name.
What is a simple way to make a clone of the app that will allow me to make code changes to one version, merge them with the new version (or versions), but keep the package name?
Or should I have everything in one project folder and then write and run some script that will change package names and swap content files? My iOS friend will probably need a few different #defines, but what should I do here, so I can maintain both versions in the future?

declare your original project as library, then create 2 new projects each for one language and let them include original project as library
then you can go ahead and just override bitmaps and constants you need.
this way, if you need any changes in core functionality, you just change your library project, and changes will propagate to both of extending projects
read more about library projects here:
https://developer.android.com/tools/projects/index.html#LibraryProjects

Manage code/build for Android app stores (Google/Amazon/etc)?

I have an Android app that's downloaded primarily from Android Market (now, Google Play). We made a few tweaks to the source and also submitted to the Amazon App Store to see what sort of traction it gets. I'm now looking for a sustainable way to develop from a common code base and yet build so that I can submit to either/both.
Amazon's store has some restrictions about available APIs, and hence I'd like to conditionally remove/modify features from that version. Since Java doesn't support traditional conditional compilation, and conditionally including files in Eclipse doesn't seem trivial (is it even possible?), I wanted to ask what others are doing to solve this.
Admittedly, I'm no Eclipse/Java expert so feel free to school me.
What I'm looking for in a solution:
Building/debugging using Eclipse.
Static code files, with environment/settings toggles to control what to build.
No duplicate code or conditional logic in code to pick code flow at runtime
Is this something you've solved for Android apps specifically, or for other Java/Eclipse based projects? Suggestions for where to begin?

It's quite easy to do in the newest versions of ADT (version 17), though I do find it makes compilation a bit longer:
Create a new Android project (proj-A)
Go to Project->Properties, select Android, and check "Is Library"
Move all your common code to proj-A, import all the necessary libraries
Create a new Android project for Google Play (proj-B)
Go to Project->Properties, select Android, and add Proj-A to the Library
Repeat #4&5 for the Amazon version
If you have some variables that should be set differently for each sub project (i.e. boolean GOOGLE_PLAY_VERSION to enable Google Play specific functions), you have to create another project to contain these values since you can't have projects that reference one-another in a circular fashion. You can solve this by adding the following steps:
Pull all of your sub-project specific variables into one or more Classes that just serves as container(s) for these variables
Create a "dummy" Java project (dummy)
Config proj-A to add a new Source link to the bin directory of dummy
Add the config Classes in each sub-project with project-specific changes
Profits!
Note that the variables in dummy should not be set as final, otherwise it will override sub-project's setting.
This may seem like quite a bit of up-front work, but has worked quite well for me as far as version control goes.
Edit:
Now with Google's move to Android Studio & Gradle, it may be better to move to that if you are starting a new project if you want to support multiple APKs, see Android dev site's Building Your Project with Gradle#Work with build variants. It definitely doesn't hurt to evaluate that option before deciding.

Unfortunately, it's sort of a convention in Android to change flow at runtime based on what would be in C/C++-land conditional compilation.
Our app has to maintain different behavior for different API levels, so we've created some application-level constants that are initialized statically based on API-level information available to us, and used throughout the code. This is the way that Google does things in their examples (for example, see the ActionBarCompat compatibility library, and in particular the factory method used here).
You could create an interface CustomBuild, and implement it in AmazonBuild and GooglePlayBuild, then use a static getBuild() method to switch functionality as necessary:
if(getBuild().shouldEnableFeatureX()){
doStuff();
} else {
doDifferentStuff();
}
Then all you've got to worry about switching between builds is a line or two of code in the factory along with maintaining which things you want enabled in which versions. Or you could include a different version of a static class CustomBuild for each build.
I'm going to second the suggestion of others above re: switching to something like Maven for building; it should make your life much easier once you have it set up.
I'm also going to say you should make the core of the app a library as suggested above, and have two different modules (one for amazon, one for play store) that depend on the library but each only contain the one custom factory file (or just a static class for each type of build that contains the same "should I do this thing?" methods... once you have the infrastructure it's just a matter of preference).

I haven't actually tried this yet, but it's something I've thought about.
How about using Eclipse's ability to link to files from a directory outside your workspace?
Start with one Eclipse project: for the sake of argument, say it's the Google Play version.
Now build a second project, beginning with asking Eclipse to link (not copy) the source files from your first project.
To develop the second project, add classes that subclass ones from the original project to realize your modifications. For resources, you can use some combination of includes, attribute overrides, and selectors.
Where it's not possible to subclass or extend, then obviously you'll have to just copy the original source file and hack on it. If you're really OCD about it, you can probably just maintain a patch set rather than a whole redundant set of files.
What do you think, will it work?

You may create manually two projects in Eclipse pointing to the same source folders but with different inclusion/exclusion filters and different target directories.
Then two Ant targets using properties to switch excluded files from javac fileset are enough to generate corresponding jar files.
The aim is to get a clean application for each target, without any code from the other one.
With features listed as pluggable behaviors in a property file or XML configuration, your runtime will adapt itself with the addition of menu entries.

Multiple Android Application Package .apk files from single source code

I would like an Android build system procedure, command line or Eclipse, to generate several .apk files from a single source codebase. Some common reasons for this - having specific versions for markets with different requirements or a free and paid version.
This question IS NOT ABOUT:
Packaging shared code into Android libraries or into external Java jars
Producing a debug vs. signed release .apk
Google says "you probably need to create separate Android projects for each APK you intend to publish so that you can appropriately develop them separately. You can do this by simply duplicating your existing project and give it a new name." Then they kindly suggest using libraries, which I understand. Then, they mention in passing exactly what I do want: "a build system that can output different resources based on the build configuration"
I know that to accomplish conditional compilation in JAVA one can key off a 'public static final' variable. There is an example of tweaking such a value in build.xml. Any more complete example of an Android Ant build configuration for this or a link to an OSS project doing that now, please? BTW, build.xml is auto-generated, but I have seen people hacking it, so how does that work?
With the package name declared in Manifest.xml as package="com.example.appname", if one needs to emit multiple .apks that vary that name, is one stuck with a separate project for each?

I'm generating 2 different APK's (demo and production) from one single source tree with 3 small modifications:
1) I have public static final DEMO=true; //false; in my Application class and depending on that value I used to switch code between demo/production features
2) There are 2 main activities, like:
package mypackage;
public class MyProduction extends Activity
{
//blah-blah
}
package mypackage.demo;
public class MyDemoActivity extends mypackage.MyProductionActivity
{
//blah-blah
}
3) And in the end 2 separate AndroidManifest.xml files which points to different launcher activities depending on demo/production switch
I'm switching between 2 APK's manually, but see nothing difficult in writing small ANT task to switch between them automatically

One way to do it would be to maintain two separate AndroidManifest.xml, one for each configuration. You can switch back and forth between the two either manually (copying) or automatically (build script).
[edit] This person here has a system to do this kind of thing: http://blog.elsdoerfer.name/2010/04/29/android-build-multiple-versions-of-a-project/

The answer to this screams Gradle, as explained on this website. It's officially built into Android Studio and is encouraged.
It's amazing; I've built 3 separate apps using the same source code, with customized text and graphics, with no special coding whatsoever. Just some directory and Gradle setup is required, and other posts of mine can be found with answers to both.
It seems to explain all the basics really well. For the answer to your specific question, look for the section Product Flavors under Build Variants, where it describes specifying different flavors.
As the website explains, part of the purpose behind this design was to make it more dynamic and more easily allow multiple APKs to be created with essentially the same code, which sounds exactly like what you're doing.
I probably didn't explain it the best, but that website does a pretty good job.

Despite your insistence that this is not about packaging shared code into Android libraries, it sort of is. You've stated that markets may have different requirements or having a free and a paid version. In each of these examples, your two final output APKs have different behavior and/or resources. You can put the vast majority of your code in a shared Android library, and then maintain the differences in your actual projects.
For example, I've worked on apps where they need to be released both to the Android Market and the Amazon AppStore. The Amazon AppStore requires that if you link to a market page for the app, it must be Amazon's (as opposed to the Android Market page). You can store a URL in a resource in the library and use that in your code, but then override that resource in the Amazon project to point to the appropriate Amazon URL.
If you structure it right, you can do similar things in code because your starting point is your Application object which you can subclass and do different things with.
That said, if you want to add an Ant step that changes the package name in the manifest, it is just XML. It shouldn't be hard to modify as a precompilation step.

This article has a good walk-through with examples of how to amend config files at build time; see in particular the Customizing the build and Using a Java configuration file sections. Note that some of the information about build.xml and ant is a little bit out-of-date now.

Here's our situation: we have a single codebase from which we release for several clients. Each of them has various requirements regarding titles, backgrounds and other resources in the application (let alone package names).
Build is handled by a Ruby script that modifies AndroidManifest, copies/replaces certain resources from client-specific folders and then moves on to Android's standart build routine. After the build is done, script resets changed files back to their original, 'default' state.
Well... Maybe it's not optimal and definitely not Android-specific, but that's how we do it.

I had the same problem but packing all in one project with flags is no solution for me. I wrote an example how to do that with Maven:
How to create multiple Android apk files from one codebase organized by a Maven multi module project.

My team build 2 different build using single code base + additional code.
As android build is based on ant script, I use ant script to do this work.
I used xmltask to manipulate manifest xml file and many ant task ( regexp , copy..) to edit source code.
I prepared template project template ( including build.xml , default.properties, local.properties) and copied new source code into those project templates. when copy completed, run build.xml parallel to shorten build time. when build finished, I get multiple apk files.

It's easily to achieve your goal by using Android Studio build variants which use graddle as the build system.
Check here for more detailed information.

I think that the best way remain to use libray for common sources and two different Android project for demo and production package. This because in Java it is very simple to make a reverse engeneering from apk to sources. If you use the same sources for demo and production, someone could hacking your apk downloading the demo package, extracting the java sources and unlock the sources changing the variable to use it as production version.
With library you can preserve part of sources in the production package, in this way there is no way to use demo package as production package.